Cascade solves global irrigation issue

Amalshan Gunerathna

The cascade-based small tank system in Anuradhapura which withstood the test of time and lasted for over two millennia required rehabilitation. Plan Sri Lanka - internationally reputed community development organization - took up the challenge of restoring the system to its former glory. Their project is spanned between 2004-2010.

Project’s team leader Professor C M Madduma Bandara shares his ideals on the status quo of the irrigation system and what the future holds for the system expansion.

How would you explain cascade irrigation system?

The concept is not so popular. I introduced the word cascade in 1985. Basically it is related to small tank systems in the dry zones. The cascade is nestled in small catchments; you have several tanks in one system. The water is passed from one tank to another.

What is the difference between tank as single entity and a nestled cascade system?

If you look at the history, up to 1985, even Irrigation Department and other water resource management divisions treated tanks as a single entity. But later they discovered you cannot treat a tank as a single entity because it functions as a connective chain. True, the tank is basically the key point, but tanks are not isolated. Every tank gets water from a tank above. Therefore if you take one tank as a separate entity, as it was done before, then the most precious element, water, cannot be managed wisely.

Despite its importance, why was the cascade concept not adequately utilized in the past?

It was after 1985 that the term came in to practice. But unfortunately with regard to the renovation and the rehabilitation of tanks it had not been used until 1985. Even afterwards, I think the government agencies did not focus their attention to it. But North Central Provincial Council accommodates this concept and they have a separate section on how to develop it. It is for the first time an NGO, Plan Sri Lanka, took the initiative to pioneer and rehabilitate this system.

Does the international community show any interest in cascade irrigation development?

Yes, these cascade systems are internationally noted. In fact the cascade system is more spoken of outside the country. There are even students who want to do PhDs on this subject, because of the importance.

What is the present condition of the irrigation system? Do you think the heavy use of agrochemicals and deforestation affects the village tanks and the community health?

Well every year nearly 4000 people die in Anuradhapura hospital because of kidney diseases. Nobody knows how it happens, but everybody suspects that it has something to do with chemicals. In a way the tank is a receptacle for pollutants. It is an unfortunate scenario, and people’s lives are at risk. Our results show that in a cascade variations do take place and it also affects the fish. For instance traditional fish varieties are no longer there.

Can you explain how cascade approach can help face the negative impacts of global climate change?

This system has been very robust. Otherwise it would not have lasted for 2000 years. It can survive floods, it can help in droughts and it can preserve the biodiversity. As for the climate change, it is not a problem created by us. It was created by the West and more industrialized countries. At the root of it is the western civilization. Based on individualism and consumerism they have created the global crisis. But now they look for models to combat this crisis. And here we have a model.

If we develop the cascade system into its full potential do you think it will have a positive impact on the country’s development process?

In several ways, I think it will be very beneficial. But we still have to experiment. Even the Plan’s mandate has to be reconsidered because we were not supposed to be a research organization. But there are issues which have to be handled with new research. So what we proposed is at least if we can develop a few model cascade systems, we can experiment with them and probably show it to the rest of the country or even to the rest of the world.

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Joint effort

PLAN Sri Lanka, an internationally reputed community development organization, in collaboration with Central Environmental Authority (CEA) organized a national conference on ‘Cascade Irrigation Systems for Rural Sustainability’ at the Sri Lanka Foundation Institute in Colombo on December 9.

The main objective of this conference was to discuss and disseminate the lessons learned from a cascade based small tank rehabilitation project that Plan carried out in Anuradhapura district. The project was a joint effort to rehabilitate the cascade irrigational technology that withstood the test of time and lasted for over two millenniums.

PLAN Sri Lanka worked in partnership with government ministries, departments, farmer organizations and communities on developing the cascade systems with an interdisciplinary approach. The project strategy included activities such as community mobilization and participation, building of farmer organizations, and rehabilitation of infrastructure in cascades.

The inauguration session of the conference was followed by a technical session on Cascade concept and its applications where they defined the concept and did a very analytical discussion on the origins of the cascade system. Then they went on to discuss the value of the system and the way in which it could combat the negative impacts created by global climate change.

Central Environment Authority (CEA) has given full support to the projects carried out by PLAN Sri Lanka. Speaking to Daily News CEA Chairman Charitha Herath said: “As the regulatory arm of the environmental management, we felt this would be a timely initiative we could also take part in. I am really happy to take part in this.”